Fracture fixation plate for the proximal radius

ABSTRACT

A system for the internal fixation of a fractured bone of an elbow joint of a patient includes at least one bone plate, each bone plate having a plurality of holes and generally configured to fit an anatomical surface of the fractured bone. The at least one plate is adapted to be customized to the shape of a patient&#39;s bone. The system also includes a plurality of fasteners including at least one locking fastener for attaching the bone plate to the bone. At least one of the holes is a threaded hole. Guides for plate benders, drills, and/or K-wires can be pre-assembled to the threaded holes, and the locking fastener can lock into any of the threaded holes after the guides are removed.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims benefit of Ser. No. 60/985,000, filed Nov. 2,2007, which is hereby incorporated by reference herein in its entirety.

FIELD OF THE INVENTION

The subject matter of this disclosure relates broadly to surgicaldevices and methods for the internal fixation of fractured bones, andmore particularly, to bone plates and fasteners.

BACKGROUND OF THE INVENTION

The three long bones of the upper extremity are the humerus, radius andulna. The distal portion of the humerus and the proximal portions of theradius and the ulna form the elbow joint. Elbow fractures account foronly about 5-8% of all fractures and occur most commonly in older peopleas a result of a fall. The functional outcomes of elbow fractures ofteninclude high rates of joint stiffness, loss of range of motion andnon-union.

Orthopedic surgeons generally follow certain principles for the properinternal fixation of the bones of the elbow joint. Each screw used toattach the plate to the bone should be as long as possible and engage asmany articular fragments as possible. The screws should lock to theplate and interdigitate to create a “fixed angle” structure. The platemust be strong and stiff enough to not break or bend under load.Adhering to these principles for elbow fracture repair is particularlychallenging given the difficulty of the surgical procedure and theanatomical variation among patients.

In addition, a bone plate attached to the surface of a fractured bone ofthe elbow joint may tend to stand “proud” of the bone surface. Currentlyavailable plates do not fit well on the bone surfaces without impingingon soft tissue or obstructing the natural articulation of the joint. Onebone plate shape, even if provided for each type of elbow fracture andin different sizes, cannot accommodate all the anatomical differencesamong patients.

About half of all elbow fractures are radial head fractures and about afifth involve fracture of the radial neck or proximal radius. Because ofthe considerations just stated, surgeons generally prefer not to usebone plates to treat the fractured proximal radius. Depending on theextent of comminution of proximal radius fractures, surgeons may insteaduse external fixation or screws and pins together with post operativetherapy.

Fractures of the coronoid, which is located on the proximal ulna, aretypically small but difficult to treat. Proper treatment is importantsince the coronoid fracture may have a heavy impact on overall elbowstability. Traditional fixation of these fractures involve capture ofthe coronoid fragments with screws or sutures coming from the posteriorside of the ulna. This type of fixation may not be stable enough toresist the strong anterior dislocating force of the distal humerus.

The olecranon is located on the posterior side of the proximal end ofthe ulna and articulates in the olecranon fossa. The olecranon is notcovered with thick layers of soft tissue and is particularly vulnerableto external impacts and fracture. The olecranon also is the attachmentlocation of the triceps muscle used in extension of the arm, andtransfers very high forces.

In addition to fractures of the olecranon, the surgeon may intentionallysever the olecranon from the proximal ulna during an osteotomy procedurein order to reflect the triceps muscle, thereby obtaining improvedsurgical access to the distal humerus. Once the repair to the humerushas been completed, the surgeon then may use a bone plate to reattachthe olecranon to the proximal ulna.

Currently available fracture fixation plates for the medial, lateral andposterolateral parts of the distal humerus do not consistently match thecontour of the bone surface. Due to the anatomical differences betweenpatients, a single bone plate configuration, as initially provided tothe surgeon, is unlikely to conform perfectly to the bone surface, evenif that plate was specifically designed for that particular type ofbone. Therefore, some manufacturers provide numerous sizes andconfigurations of bone plates for a particular portion of a specificbone. Since selecting the right plate involves subjectivity, clinicaloutcomes may not be highly consistent.

SUMMARY OF THE INVENTION

A system of bendable plates is provided that may be easily and safelyreconfigured inside the patient's body (in situ) during the surgicalprocedure. The system can be reconfigured without distorting the shapeof bone fastener holes in the plate, and any threads within the holes.The system includes and is adapted for use with in situ bending tools toreconfigure the plate inside the patient's body during the surgicalprocedure.

A system of low profile bone plates and fasteners are provided for theinternal fixation of the fractured bones of the elbow. The elbow jointis not protected with thick layers of soft tissue. The plates of thesystem of the invention have minimal thickness and conform closely tothe bone surface. In addition, it is very important that the heads ofall fasteners used to attach the plate to the bone not protrudesignificantly, if at all, above the top surface of the plate. A “proud”fastener head may lead to soft tissue irritation, inflammation or othertypes of trauma that may cause complications and patient discomfort.

An elbow fracture fixation system is provided that also includes lockingfasteners for attachment of the bone plate to the fractured bone. Ingeneral, the primary functions of various bone plates of the system(which are all adjacent near the elbow joint) include not only holdingthe bone fragments together in healing alignment, but also the transferof forces from the metaphysis to the diaphysis of the fractured bonewhile the bone is mending. The system allows the distal tip of afastener to be anchored into healthy, cortical bone, and the transfer offorce from the healthy bone to the plate, such that the plate properlyaccomplishes load sharing.

A system for elbow fixation is provided with includes a number oflocking fasteners, each having an optimal trajectory, directly beneaththe articulation surface of the fractured bone to create a scaffold fortransferring forces from the articulating surface to the bone plate.

A system for the internal fixation of a fractured bone of an elbow jointof a patient has at least one bone plate, each bone plate having aplurality of holes and configured to fit an anatomical surface of thefractured bone. The system also has a plurality of fasteners includingat least one locking fastener for attaching the bone plate to the bone.At least one of the holes is a threaded hole and the locking fastenercan lock into the threaded hole.

The locking fastener may be a fixed-angle locking fastener or amultidirectional locking fastener. The system may also have at least onenon-locking fastener and the threaded hole can receive the non-lockingfastener. The non-locking fastener may be a multidirectional compressionfastener. The bone plate may also have a plurality of threaded holes anda plurality of drill guides. Each drill guide has a bore sized forguiding a drill and a proximal portion that is engageable with a toolfor removal of the drill guide from the threaded hole. Each drill guideis removably preassembled into one of the plurality of threaded holes.The system also may have a first bending tool and a second bending tool.Each bending tool has an elongated rod having a handle and an endeffector at one end of the elongated rod and adapted for removableengagement to the drill guide. A user may removably attach the firstbending tool to one of the drill guides and the second bending tool toanother of the drill guides and then simultaneously apply a leveragingforce to each of the first and second bending tools, therebyreconfiguring the bone plate. The bone plate of the system may be atleast one of a radial plate for fixation of the proximal radius bone, anolecranon plate for fixation of the olecranon of the proximal ulna bone,a coronoid plate for fixation of the coronoid process of the proximalulna bone, a lateral plate for fixation of the lateral distal humerusbone, a medial plate for fixation of the medial distal humerus bone, anda posterolateral plate for fixation of the posterolateral distal humerusbone.

According to another aspect of the system, a bone plate for the proximalradius has a rigid body with proximal and distal ends defining alongitudinal axis, a medial edge and a lateral edge. The bone plate alsohas a first arm extending from the rigid body. The first arm has a firstring element attached to the body by a first curved bendable bridgeelement. The rigid body has a central hole and the first ring elementincludes a first hole. Each of the central and first holes can receive afastener for attaching the bone plate to the bone.

Still referring to the bone plate for the proximal radius, the centralhole may be threaded and define a central axis, and the first hole maybe threaded and define a first thread axis. The first arm may extendfrom the rigid body proximal-medially, and the first curved bendablebridge may be attached to the medial edge of the rigid body. The boneplate may also have a second arm extending proximal-laterally from therigid body and including a second ring element attached to the lateraledge of the rigid body by a second curved bendable bridge element, thesecond ring element including a second hole having a thread that definesa second thread axis. The bone plate may also have a third arm extendingproximally from the rigid body and including a third ring elementattached to the proximal end of the rigid body by a third bridgeelement, the third ring element including a third threaded hole defininga third thread axis. The first, second and third arms form a fork-likestructure and the first, second and third thread axes converge but donot intersect. The bone plate may also have a fourth arm extendingdistally from the rigid body. The fourth arm may have a fourth ringelement attached to the distal end of the rigid body, the fourth ringelement having a fourth threaded hole defining a fourth thread axis. Thebone plate may also have a first, a second, a third and a central drillguide preassembled into the first, second, third and central holes,respectively. Each of the first curved, second curved and third bendablebridge elements is less stiff than the rigid body, but togetherpreferably have a combined stiffness that approximates the stiffness ofthe rigid body. Each of the first, second and third drill guides isadapted for application of a bending tool, such that a user may use apair of bending tools to apply a leveraging force to reconfigure any oneof the first, second and third arms. The bone plate may also have afifth arm extending distally from the fourth ring element. The fifth armmay have a fifth ring element attached to the distal end of the rigidbody by a fifth bendable bridge element. The fifth ring element may havea fifth threaded hole for receiving a fastener, and have a fifth drillguide preassembled into the fifth hole. Each of the fourth and fifthbendable bridge elements is less stiff than the rigid body, and each ofthe fourth and fifth drill guides is adapted for application of abending tool, such that a user may use a pair of bending tools to applya leveraging force to reconfigure either of the fourth and fifth arms.The fourth and fifth bendable bridge elements may also be fragmentable,such that a user may use the pair of bending tools to apply a leveragingforce to fatigue fracture the fourth bendable bridge element in order toremove the fourth and fifth arms, and to apply a leveraging force tofatigue fracture the fifth bendable bridge in order to remove the fiftharm.

According to another aspect of the system, bone plates for the lateraland medial surfaces of the distal humerus each have a rigid body portionwith substantially the same thickness. The rigid portion of each of themedial and lateral plates has a distal end, a proximal end, a topsurface, a bottom surface, a medial edge and an opposing lateral edge.The plates also have a plurality of holes extending between the top andbottom surfaces, each of the holes for receiving a fastener forattachment of the bone plate to the bone. The lateral bone plate alsohas at least one positioning foot extending from an edge downwardlytowards the bone surface to aid in the positioning of the bone plate onthe bone surface.

Still referring to the bone plate for the lateral and medial surfaces ofthe distal humerus, the bone plates may also each have a first segmentattached to the distal end of the rigid body portion by a first bendablebridge element that is longitudinally aligned along one of the medialand lateral edges of the rigid body portion, and the first segmentincludes a threaded hole for receiving one of the fasteners. The boneplates may each also have a proximal edge of the first segment, and theproximal edge and the distal end of the rigid body are spaced apart anddefine a gap, and the gap includes a throat opening adjacent to thefirst bendable bridge element and is configured for guiding a K-wirepassed therethrough. The bone plates may also each have a second segmentattached to the distal edge of the first segment by a second bendablebridge element that is longitudinally aligned with the first bendablebridge element, and the second segment includes a threaded hole forreceiving one of the fasteners. The bone plates may also each have oneor more elongated slot for receiving a compression fastener, and thelength of the slot is greater than the width of the slot and the lengthis oriented in the longitudinal direction of the respective bone plate.The lateral plate includes recesses at the bottom surface of the plateon at least one side, and preferably both sides, of the elongated slotto permit clearance for screw angulation toward the center of the bonefor improved purchase of the screws. The thickness of the rigid bodyportion on respective medial side and lateral sides of the slots mayalso be thinner than the average thickness of the rigid body portion foreach of the medial and lateral plates. The bone plates may also eachhave an hourglass-shaped opening extending between the top and bottomsurfaces, and the hourglass-shaped opening has two ends, each of whichare configured to guide a K-wire passed therethrough. The proximal endof each of the bone plates may also be tapered. The thickness of thefirst bridge element may also be less than the thickness of the rigidbody portion. The bone plate may each also have a distal threaded holenear the distal end of the rigid body, a distal tall drill guidepreassembled into the distal threaded hole, and a first tall drill guidepreassembled into the first threaded hole. The distal and first talldrill guides may be adapted for application of a bending tool, such thata user may use a pair of bending tools to apply a leveraging force toreconfigure the first bendable bridge, thereby repositioning the firstsegment to a desired orientation with respect to the bone. The boneplate may each also have a plurality of proximal threaded holes locatedin the rigid body portion near the proximal end, and a like plurality ofshort drill guides, and each of the proximal threaded holes ispreassembled with one of the short drill guides.

According to another aspect of the system, a bone plate for theposterolateral surface of the distal humerus has a body with a thicknesssubstantially greater than the medial plate (greater than fifty percentthicker). The body has a proximal end, a distal end and a curvilinear,longitudinal axis extending therebetween. A first arm and a second armextend from proximal end on opposing sides of the longitudinal axis,thereby forming a Y-shape, and a third arm extends transversely awayfrom the longitudinal axis to extend partially around the lateral sideof the distal humerus. The first, second, and third arms each includes aring element having a hole and are attached to the body by respectivebendable bridge elements. The body includes threaded holes and anelongated slot, each of which may be located along the longitudinalaxis. The slot may be configured to receive a compression fastener. Eachof threaded holes is configured for receiving one of the fasteners. Thethreaded holes may be preassembled with a plurality of drill guides,with a proximal hole receiving a short drill guide. In the same manneras with the lateral and medial plates, the surgeon may closely match theshape of posterolateral plate to the bone surface and redirect thetrajectories of the fasteners to capture bone fragments and avoidfracture lines and other fasteners.

According to the system, the medial and lateral plates can be usedtogether in a surgical approach that positions the plates in arelatively parallel configuration on opposite sides of the distalhumerus bone. Alternatively, the medial and posterolateral plates can beused together in a surgical approach that positions the plates in arelatively orthogonal configuration on the distal humerus bone. Ineither configuration, the resulting system of plates has substantiallysimilar stiffness on the distal humerus bone.

According to another aspect of the system, a bone plate for the coronoidhas a plurality of ring elements including a central ring element, eachof the ring elements having a threaded hole for receiving a lockingfastener. The bone plate also has a plurality of bendable bridgeelements interconnecting the ring elements, and the plurality of ringelements are arranged into a plurality of arms extending radially fromthe central ring element.

Still referring to the bone plate for the coronoid, the plurality ofarms may include a first arm extending distally from the central ringelement, a second arm extending medially from the central ring elementand a third arm extending laterally from the central ring element. Thefirst arm may have three of the plurality of ring elements spaced apartand arranged linearly, and the second arm may have one of the pluralityof ring elements, and the third arm may have one of the plurality ofring elements. The bone plate may also have a buttress element attachedto one of the plurality of ring elements by a bendable web element, andthe bendable web element is reconfigurable in situ such that thebuttress element can bear against the bone surface. The buttress elementmay extend proximally from the central ring element. The buttresselement also may extend medially from the ring element of the secondarm. The bone plate may also have a plurality of drill guides, and eachof the ring elements is preassembled with one of the drill guides. Thedrill guides may be removably attachable to a bending tool, such that auser may use a pair of bending tools to apply a leveraging force toreconfigure, in situ, each of the first, second and third arms.

According to another aspect of the system, a bone plate for theolecranon has a body portion having a distal end, a proximal end, alongitudinal axis, a medial edge and a lateral edge. The bone plate alsohas a head portion transversely positioned on the distal end of the bodyportion. The bone plate also has a proximal arm extending proximallyfrom the head portion and including a proximal ring element attached tothe head portion by a proximal bendable bridge element, such that theproximal arm is reconfigurable in a sagittal plane containing thelongitudinal axis and perpendicular to the top surface. The bone platealso has a plurality of threaded holes, and each threaded hole defines athread axis and can receive a fixed-angle locking fastener for attachingthe bone plate to the bone.

Still referring to the bone plate for the olecranon, the proximal ringelement may have at least one threaded hole, and the body portion mayhave a plurality of threaded holes aligned longitudinally, and the headportion may have two threaded holes aligned transversely. The two threadaxes of the head portion are transversely offset from the thread axis ofthe proximal ring element, such that when the proximal arm isreconfigured in the sagittal plane in a direction to result in thethread axis of the proximal ring element to converge with the two threadaxes of the head portion, the thread axis of the proximal ring elementpasses between the two thread axes of the head portion. The bone platemay also have a medial arm extending medially from the body portion andincluding a medial ring element attached to the medial edge of the bodyportion by a medial bendable bridge element. The bone plate may alsohave a lateral arm extending laterally from the body portion (oppositeof the medial arm, where provided) and including a lateral ring elementattached to the lateral edge of the body portion by a lateral bendablebridge element, and each of the medial and lateral ring elements mayhave a threaded hole defining a thread axis for receiving a fixed-anglelocking fastener. The medial and lateral bridge elements are configuredsuch that the axes through the holes of the medial and lateral ringelements generally converge toward each other, but do not extend withina common plane. The bone plate may also have a plurality of drillguides, wherein each of the threaded holes is preassembled with one ofthe drill guides. The drill guides may be removably attachable to abending tool, such that a user may use a pair of bending tools to applya leveraging force to reconfigure, in situ, each of the medial, lateraland proximal arms. The bone plate may also have a slot in the bodyportion for receiving a non-locking compression fastener.

According to another aspect of the system, a bone plate has a tapered,threaded hole configured for receiving a fixed-angle, locking fastenerhaving a tapered, threaded head to engage the tapered, threaded hole forattaching the bone plate to the bone, the threaded hole defining a holeaxis. The system also has a multidirectional compression fastener forinsertion into the tapered, threaded hole for attaching the bone plateto the bone. The multidirectional compression fastener has an elongatedshank portion having proximal and distal ends and defining a fasteneraxis. The multidirectional compression fastener also has a smooth,frustoconically shaped head with a large diameter end and a smalldiameter end, and the small diameter end is attached to the proximal endof the shank portion, and the large diameter end has a circular,peripheral edge that defines a proximal face with a recess for receivinga driving tool. The multidirectional compression fastener is fullyinsertable into the tapered, threaded hole, such that the smooth,frustoconically shaped head compresses against the tapered, threadedhole, and the fastener axis and the hole axis define an insertion angle.

Still referring to the multidirectional compression fastener, theelongated shank may be at least partially threaded for engagement intothe bone. The insertion angle may range from zero to about 15 degreesand may be contained in any plane containing the hole axis. Thecircular, peripheral edge may also have an external radius. The smooth,frustoconically shaped head may define an included angle of about 42degrees centered on the fastener axis. The system may also have a slotextending through the thickness of the bone plate, and the slot is sizedand configured to receive a conventional compression screw having aspherical head. The system may also have a washer for receiving themultidirectional compression fastener. The washer has a boretherethrough for receiving the multidirectional compression fastener andan outer surface sized and shaped similarly to the spherical head of theconventional compression screw, such that the multidirectionalcompression fastener and the washer may be used in combination in theslot in a similar manner as a conventional compression screw to aid inthe reduction of the bone fracture and to attach the bone plate to thebone. A portion of the bore of the washer may be conically shaped, suchthat the proximal face of the multidirectional compression faster isapproximately flush with the top of the washer when fully inserted intothe washer. In a preferred embodiment, the screw and washer areengageable together such that they may be handled together as a unitduring a surgical procedure.

According to another aspect of the system, the system has a bone platehaving a threaded hole defining a thread axis for receiving a fixedangle, locking fastener. The system also has a drill guide preassembledinto the threaded hole, the drill guide including a drill guide boresized to guide a bone drill. The system also has an insertion toolhaving a cylindrical body with distal and proximal ends and alongitudinal axis extending therebetween. The cylindrical body has agrip surface for holding the insertion tool during use. The cylindricalbody also has a longitudinal bore extending between the distal andproximal ends and sized for guiding a K-wire, and the distal end isconfigured to be removably attached to the drill guide so that thelongitudinal bore aligns with the thread axis. The distal end of theinsertion tool may also fit securely into the drill guide, such that theuser may use the cylindrical body as a handle to manipulate the boneplate during the surgical procedure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an anterior (front) view of the bones of the human elbowjoint;

FIG. 2 is a posterior (back) view of the bones of the human elbow joint;

FIG. 3 is a top perspective view of a proximal radius plate;

FIG. 3A is a top perspective of a smaller version of a proximal radiusplate;

FIG. 4 is a bottom perspective view of the proximal radius plate of FIG.3;

FIG. 5 is a perspective view of a pair of bending tools as they may beapplied in situ to reconfigure the proximal radius plate of FIG. 3;

FIG. 6 is perspective view of the bending tools of FIG. 5 as they may bealternately applied in situ to reconfigure the proximal radius plate ofFIG. 3;

FIG. 7 is a bottom perspective view of the proximal radius plate of FIG.3 with a plurality of fasteners fully inserted;

FIG. 8 is a wire frame, lateral view of the proximal radius plate ofFIG. 3 attached with a plurality of fasteners to the proximal radius;

FIG. 9 is a top, medial perspective view of a lateral plate for thedistal humerus;

FIG. 10 is a top, lateral perspective view of the lateral plate of FIG.9;

FIG. 11 is a bottom perspective view of the lateral plate of FIG. 9;

FIG. 12 is a top perspective view of a medial plate for the distalhumerus;

FIG. 13 is a bottom perspective view of the medial plate of FIG. 12;

FIG. 14 is an anterior, transparent view of the distal humerus with thelateral and medial plates of FIGS. 11 and 12 attached thereto by aplurality of fasteners;

FIG. 15A is a top perspective view of a posterolateral plate for thedistal humerus;

FIG. 15B is a bottom perspective view of the posterolateral plate ofFIG. 15A;

FIG. 16 is top perspective view of the posterolateral plate of FIG. 15A,shown preassembled with a plurality of first drill guides;

FIG. 17 is top perspective view of the posterolateral plate of FIG. 15A,shown with a plurality of fasteners fully inserted;

FIG. 18 is a wire frame drawing of the posterolateral plate of FIG. 15Aattached to the posterolateral surface of the distal humerus;

FIG. 18A is posterior, transparent view of the distal humerus with themedial and posterolateral plates of FIGS. 12 and 15A attached thereto bya plurality of fasteners;

FIG. 19 is a top perspective view of a coronoid plate;

FIG. 20 is a bottom perspective view of the coronoid plate of FIG. 19;

FIG. 21 is wire frame view of the coronoid plate of FIG. 19 attached tocoronoid of the proximal ulna;

FIG. 22 is a transparent view of the coronoid plate of FIG. 19 attachedto the coronoid of the proximal ulna;

FIG. 23A is a top perspective view of an olecranon plate;

FIG. 23B is a bottom perspective view of the olecranon plate of FIG.23A;

FIG. 23C is a bottom perspective view of the olecranon plate of FIG.23A, including a plurality of fasteners fully inserted;

FIG. 24 is top perspective view of the olecranon plate of FIG. 23Apreassembled with a plurality of first drill guides of FIG. 41;

FIG. 25 is a transparent side view of the olecranon plate of FIG. 23Aattached to the olecranon of the proximal ulna;

FIG. 26 is a top perspective view of another embodiment of an olecranonplate;

FIG. 27 is a head end view of a conventional compression screw;

FIG. 28 is a side view of the compression screw of FIG. 27;

FIG. 29 is a head end view of a multidirectional locking screw;

FIG. 30 is a side view of the multidirectional locking screw of FIG. 29;

FIG. 31 is a cross-sectional view of the multidirectional locking screwof FIG. 29 inserted into a threaded hole of a bone plate;

FIG. 32 is a perspective view of a fixed-angle locking screw;

FIG. 33 is a head end view of the fixed-angle locking screw of FIG. 32;

FIG. 34 is a detailed cross-sectional view of the proximal portion ofthe fixed-angle locking screw of FIG. 32;

FIG. 35 is a perspective view of a multidirectional compression screw;

FIG. 36 is a detailed, cross-sectional view of the multidirectionalcompression screw of FIG. 35;

FIG. 37 is a detailed, cross-sectional view of the multidirectionalcompression screw of FIG. 35 inserted into a bone plate at an insertionangle C;

FIG. 38 is a detailed, cross-sectional view of the multidirectionalcompression screw of FIG. 35 inserted into a bone plate at an insertionangle of zero;

FIG. 39 is a perspective view of a washer for use with themultidirectional compression screw of FIG. 35;

FIG. 40 is a cross-sectional view of the washer and multidirectionalcompression screw of FIG. 39 assembled into a slot of a bone plate at aninsertion angle F;

FIG. 41 is a perspective view of a first drill guide that may bepreassembled into a tapered, threaded hole of a bone plate;

FIG. 42 is another perspective view of the first drill guide shown inFIG. 41;

FIG. 43 is a perspective view of a second drill guide that may bepreassembled into a tapered, threaded hole of a bone plate;

FIG. 44 is another perspective view of the second drill guide shown inFIG. 43;

FIG. 45 is a perspective view of the first drill guide of FIG. 41 andthe second drill guide of FIG. 43 preassembled into the distal portionof a bone plate shown;

FIG. 46 is a perspective view of a distal portion of a first embodimentof a bending tool;

FIG. 47 is a perspective view of a first embodiment of a pair of thebending tools shown in FIG. 46 as they may be used to reconfigure thebone plate shown in FIG. 48 in an x-y plane;

FIG. 48 is a perspective view of the pair of bending tools shown in FIG.47 as they may be used to reconfigure the bone plate in a y-z plane;

FIG. 49 is a perspective view of a first bending tool of a secondembodiment of a pair of bending tools;

FIG. 50 is a perspective view of a second bending tool of the secondembodiment of a pair of bending tools;

FIGS. 51A-C are perspective views of the pair of bending tools shown inFIGS. 49 and 50 as they may be used to reconfigure the bone plate in ay-z plane;

FIG. 52 is a side elevation view of a K-wire insertion tool;

FIG. 53 is a perspective view of the K-wire insertion tool shown in FIG.52; and

FIG. 54 is a cross-sectional view of the distal portion of the guidewire insertion tool of FIG. 52 removably attached to the first drillguide shown in FIG. 41.

Among those benefits and improvements that have been disclosed, otheradvantages of the devices and methods described herein will becomeapparent from the following description taken in conjunction with theaccompanying figures. The figures constitute a part of thisspecification and include illustrative embodiments of the claimedinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is an anterior (front) view and FIG. 2 is a posterior (back) viewof the bones of the human elbow joint 10: the distal humerus 12, theproximal radius 14 and the proximal ulna 16. The distal humerus 12includes the coronoid fossa 18, the capitellum 20, the trochlea 22, themedial epicondyle 24 and the lateral epicondyle 26, and the olecranonfossa 28 therebetween. The proximal radius 14 includes the radial head30. The proximal ulna 16 includes the coronoid process 32 (FIG. 1) andthe olecranon 34 (FIG. 2) which articulates within the olecranon fossa28 between the lateral and medial epicondyles 24, 26 of distal humerus12. Each of the distal humerus 12, proximal radius 14 and proximal ulna16 are susceptible to a large variety of fractures, such as during afall.

The present system for the repair of elbow fractures may include aplurality of anatomically specific bone plates and a plurality offasteners for the attachment of the plates to the bone. The system mayinclude a proximal radius plate for repair of the proximal radius. Thesystem may also include a lateral plate, a medial plate and aposterolateral plate for repair of the distal humerus. The system mayfurther include an olecranon plate and a coronoid plate for the repairof the proximal ulna.

Although each of the bone plates of the system described herein aredesigned to fit closely to specific bone surfaces of the elbow joint,the plates share numerous advantages compared to conventional plates.For example, each of the plates has portions that are reconfigurable insitu, such that the surgeon may alter the bone plate shape while it ispositioned on the bone to more closely fit and support the bone surface.This also allows the surgeon to redirect the trajectories of thefasteners if necessary to capture bone fragments or to avoidintersecting other fastener trajectories.

To facilitate in situ reconfiguration of the plate using bending tools,as well as to facilitate hole drilling for rapid insertion of bonefasteners, each of the plates described herein may be preassembled witha plurality of drill guides, such as either of a first drill guide 1400shown in FIG. 41, a second drill guide 1500 shown in FIG. 43, or acombination thereof.

Each of the plates of the present system may be formed from any one ofnumerous materials known in the art, including a stainless steel, atitanium and a titanium alloy such as Ti-6Al-4V. Each of the plates ispreferably machined from a solid round bar of Ti-6Al-4V-ELI in the fullyannealed condition. Each plate is machined to its respective anatomicalshape, described below, to ensure minimal work hardening. Aftermachining, the parts are polished and anodized. The resulting platematerial is fully ‘soft’ and enable in situ shaping without fracture ofthe plate, as described in detail below. In general, each of the platesdescribed herein are significantly thinner than currently availableplates for the same types of fractures, yet still has the appropriatestiffness to support the respective fractured bone. In addition, each ofthe fasteners provided to attach the bone plates to the bone describedherein (FIGS. 28 through 38) has a low profile design, i.e., the head ofeach fastener is configured to seat relatively flush to the top surfaceof the plate, thereby minimizing trauma to surrounding soft tissues.

Each of the bone plates of the present system include a plurality ofholes, wherein each hole may be configured to receive any one of thebone fastener embodiments shown in FIGS. 28 through 40, including astandard compression screw 700 shown in FIG. 28, a fixed-angle lockingscrew 1100 shown in FIG. 32, a multidirectional locking screw 1000 shownin FIG. 30, a multidirectional compression screw 1200 shown in FIG. 35,and a multidirectional compression screw 1200 with washer 1300 shown inFIG. 40. Each of the plates of the present system includes at least onehole for receiving a locking fastener, such as either of fixed-anglelocking screw 1100 and multidirectional locking screw 1000.

Those skilled in the art will recognize that although the bone platesare described for specific elbow fracture applications, each of the boneplates, fasteners, instruments and methods described herein may beeasily modified for application to other bones and other types of bonefractures.

Bone Plate for the Proximal Radius

FIG. 3 is a perspective view of a top surface 101 and FIG. 4 is aperspective view of a bottom surface 103 of a bone plate 100 for theproximal radius, also called radial plate 100. Radial plate 100 has arigid body 102 with a proximal end 104, a distal end 106, a top surface101, a bottom surface 103 defining longitudinal axis 108 having a convexproximal portion. Rigid body 102 has a medial edge 110 and a lateraledge 112. Radial plate 100 may be symmetrically shaped as shown in FIG.3, such that it may be used on either of the right and left elbows, asdescribed in more detail below. Rigid body 102 also includes a firstcentral hole 176 and a second central hole 186, each extending betweenthe top surface 101 and the bottom surface 103, for receiving a bonefastener for attaching radial plate 100 to the bone. A first arm 120extends proximal-medially from rigid body 102 and includes a first ringelement 122 and a first bendable bridge element 124 attached to medialedge 110 of rigid body 102. Ring element 122 has a first hole 126 forreceiving a bone fastener. First bendable bridge element 124 is curvedso that first arm 120 extends initially from rigid body 102 in themedial direction, and then finally in the proximal direction. The amountof curvature shown in FIGS. 3 and 4 of first arm 120 is approximately 90degrees and not within a single plane, although the curvature may vary.The width across the first arm at B1 is less than the width across thefirst arm at B2.

As shown in FIGS. 3 and 4, radial plate 100 may also include a secondarm 130 extending proximal-laterally. Second arm 130 includes a secondring element 132 attached to lateral edge 112 of rigid body 102 by asecond bendable bridge element 134, which is also curved and opposingfirst bendable bridge element 124. As shown, second arm 130 may be, butis not necessarily, a mirror image of first arm 120. The width acrossthe second arm at B3 is less than the width across the second arm at B4.Second ring element 132 includes a second hole 136 for receiving a bonefastener.

Radial plate 100 may also include a third arm 140 extending proximallyfrom rigid body 102 and between first arm 120 and second arm 130. Thirdarm 140 includes a third ring element 142 attached to proximal end 104of rigid body 102 by a third bridge element 144 having a third hole 146for receiving a bone fastener. Each of the first, second and third arms120, 130, 140 is less stiff than the rigid body 110, but together have acombined stiffness that approximates (within 20%, and more preferably±10%) the stiffness of the rigid body. First, second and third arms 120,130 and 140, respectively, are spaced apart to form an out-of-planefork-like (preferably trident) shape, thereby allowing visualization ofthe bone surface there beneath.

Referring to FIGS. 4, 7 and 8, the first, second and third rings 122,132, and 142 are preferably relatively situated so as to be positionedapproximately about the exterior of an imaginary sphere. This adapts therings 122, 132, 142 for seating on the metaphyseal surface of theproximal radius, which is generally cylindrically curved in themedial-lateral direction and convex in the longitudinal direction, atleast at the proximal end in a manner which approximates a sphericalshape. As formed, the axes 127, 137 and 147 of the holes 126, 136 and146 criss-cross through a common central axis 190 which aligns with thepredicted center of the articular surface 192 of the proximal radius 30for which the proximal radius plate 100 is sized. When the plate isdesigned for use on larger radius bones, the central axis 190 alongwhich the holes axes 127, 137, 147 criss-cross will be further from theplate, and when the plate is design for use on smaller radius bones, thecentral axis 190 along which the hole axes 127, 137, 147 criss-crosswill be closer to the plate.

For example, FIG. 3A illustrates a radial plate 100 a scaled down insize relative to radial plate 100 to accommodate smaller radius bones.The bridge elements 124 a, 134 a, and 144 a are differently orientedrelative to bridge elements 124, 134, 144 so as to configure the rings122 a, 132 a, 142 a to define a smaller radius of curvature therebetweenso that the rings are adapted to seat on a smaller proximal radial head.The axes through the holes in the rings criss-cross closer to the plate.

Referring back to FIGS. 3, 4 and 7, as will be described further below,each of the first, second and third arms 120, 130 and 140, respectively,may be individually reconfigured, as necessary, by the surgeon to fitthe bone surface and to change the trajectories of fasteners insertedthrough the rings of such arms.

Radial plate 100 may also include a fourth arm 150 extending distallyfrom rigid body 102 along longitudinal axis 108. Fourth arm 150 includesa fourth ring element 152 having a fourth hole 156 and connected todistal end 106 of rigid body 102 by a fourth bendable bridge element154.

Radial plate 100 may also include a fifth arm 160 extending distallyfrom fourth ring element 152. Fifth arm 160 includes a fifth ringelement 162 having a fifth hole 166 and attached to fourth ring element152 by a fifth bendable bridge 164.

Each of first, second, third, fourth, fifth, first central and secondcentral holes 126, 136, 146, 156, 166, 176 and 186, respectively, ispreferably taper threaded to receive any one of multidirectional lockingscrew 1000, fixed-angle locking screw 1100, and multidirectionalcompression screw 1200.

Still referring to FIGS. 3 and 4, a plurality of drill guides may bepreassembled to radial plate 100 to facilitate drilling fastener holesinto the bone and to provide instrumentation attachment points forreconfiguring radial plate 100 during the surgical procedure. Each offirst, second, third, fourth, fifth, first central and second centralholes 126, 136, 146, 156, 166, 176 and 186, respectively, may beconfigured, such as with a tapered thread, to receive a first, second,third, fourth, fifth, first central and second central drill guide, 128,138, 148, 158, 168, 178 and 188, respectively, each of which ispreferably first drill guide 1400 (FIG. 41).

Each of bendable bridges 124, 134, 144, 154 and 164 are significantlyless resistant to bending and twisting than rigid body 102 and,therefore, individually reconfigurable with the appropriate tools, asnow described. FIG. 5 is a perspective view of a pair of bending tools2160, 2180 as they may be applied in situ to reconfigure fourth arm 150of radial plate 100. FIG. 6 is a perspective view of bending tools 2160,2180 as they may be applied in situ to reconfigure first arm 120 ofradial plate 100. Bending tool 2160 is formed into an L-shape from ametal rod, wherein one longer portion of the L-shape comprises a handle2166 and the other shorter portion comprises an arm 2168. A first endeffector 2162 is attached to the free end of handle 2166 and a secondend effector 2164 is attached to the free end of arm 2168. Each of firstand second end effectors 2162, 2164 may be securely yet removablyattached to any one of drill guides 128, 138, 148, 158, 168, 178 and 188(FIG. 3), as shown in FIGS. 5 and 6. Bending tool 2180 is also formedinto an L-shape from a metal rod, wherein one longer portion of theL-shape comprises a handle 2186 and the other shorter portion comprisesan arm 2188. A first end effector 2182 is attached to the free end ofhandle 2186 and a second end effector 2184 is attached to the free endof arm 2188. Each of first and second end effectors of either of tools2860, 2180 may be securely yet removably attached to any one of drillguides 128, 138, 148, 158, 168, 178 and 188 (FIG. 3), as shown in FIGS.5 and 6.

An x-y-z coordinate system is shown in each of FIGS. 5 and 6. The x-yplane approximately corresponds to the medial-lateral direction and thex-z direction approximately corresponds to the anterior-posteriordirection with respect to the surface of the proximal radius.

FIG. 5 shows how bending tools 2160, 2180 may be attached to bendbridges 154, 164 in the x-z plane by applying the leveraging force inthe direction of arrows 2192, or to be also used to twist bridges 154,164 about the x-axis by applying the leveraging force in the directionof the arrows 2190. Generally, equal but oppositely directed forces maybe applied to each of the bending tools 2160, 2180 to generate theleveraging force or couple. In this way, radial plate 100 may bereconfigured in situ to closely match the shape of the proximal radiussurface. This also allows the surgeon to redirect the axes of holes 156,166 into a desired direction, such as to capture a bone fragment or toavoid a fracture line or fastener already inserted into the bone.

FIG. 6 shows how bending tools 2160, 2180 may be used to twist first arm120 in the y-z plane by applying the leveraging force in the directionof the arrows 2194, or to twist first arm 120 in the x-z plane byapplying the leveraging force in the direction of the arrows 2196, suchthat ring element 122 fits closely against the proximal radius surface.Because first arm 120 has a curvature of about 90 degrees and becausethe arm is narrower at B1 than at B2, the arm 120 is structurallyadapted to sweep in a predictable manner (the twisting of arm will be ator adjacent B1) so as to minimize interaction between axis 137 and theother axes. Similarly, second arm 130 may also be reconfigured. Radialplate 100 is provided to the user with a configuration that closelymatches the majority of patients and with fastener trajectories (threadaxes) that do not intersect. However, using bending tools 2160 and 2180allows fine, in situ adjustments to improve the quality of the internalfixation. The surgeon may quickly and safely make a reasonable number ofsmall adjustments to the plate configuration without the danger ofmicrocrack formation that may lead to fracture after implantation. Abendable plate (albeit of different configuration, structure andfunction), and the in situ use thereof, and a pair of dedicated bendingtools for in situ bending of the plate are disclosed in co-owned U.S.Pub. No. 20060161158A1, 20070233111A1, and 20070233112A1, all of whichare hereby incorporated by reference herein in their entireties.

When radial plate 100 is placed on the radial head 30 (FIGS. 1 and 2),either the first or second ring elements 122, 132 of the first andsecond arms 120, 130 will generally be slightly spaced from the surfaceof the bone. The spaced apart ring will be the ring located at thelateral side of the radius bone. This configuration of the radial plate100 allows a single ‘ambidextrous’ radius plate to be used on eitherleft or right radius bones in closest possible conformation to each suchbone. The spaced apart ring may be repositioned, if desired, to seatcloser to the bone by the use of the bending tools.

FIG. 7 is a perspective view of bottom surface 103 of radial plate 100with a plurality of fasteners fully inserted, including fasteners 129,139, 149, 159, 169, 179 and 189 into holes 126, 136, 146, 156, 166, 176and 186, respectively. FIG. 8 shows the radial plate 100 attached to theproximal radius. A plurality of fasteners 129, 139, 149 and 179 form aninterdigitating, rigid scaffold beneath the articular surface of theradial head.

Holes 126, 136, 146 and 176 correspond to thread axes 127, 137, 147 and177, respectively, which may be provided in an interdigitatingarrangement, such that thread axis 127 passes between axes 137 and 177,and thread axis 137 passes between axes 147 and 127. Stated another way,axes 127, 137, 147 and 177 are all distally directed relative to thebottom surface 103 of the radius plate 100, with axis 147 beingdistalmost, axis 177 being proximalmost and extending toward a commonpoint with axis 147, and axes 127 and 137 extending transverse to eachother (76°±6° relative to each other in the medial-lateral direction)and between axes 147 and 177. Due to the curved non-planar shape offirst arm 120, when the leveraging force is applied in the directionindicated by arrows 194 in FIG. 6, first arm 120 is biased to bend inthe y-z plane, such that axis 127 may be redirected yet remain betweenaxis 137 and 177, and the corresponding fastener trajectories do notintersect. Second arm 130 is biased to bend in a similar manner, suchthat axis 137 will not intersect either of axes 147 and 127. Thisinterdigitating arrangement provides a strong, load-sharing scaffoldwhile facilitating rapid attachment of radial plate 100 to the bonesince hole re-drilling is minimized. If any of the arms 120, 130, 140are twisted or bent by the surgeon, it is important that the axes 127,137, 147, and 177 continue to interdigitate, and not conflict.

As shown in FIG. 8, fasteners 129, 139, 149 and 179 may span theproximal radius, such that the fastener tips anchor into cortical boneon the side of the bone opposite radial plate 100. A common fracturelocation is at the neck of the proximal radius head. Fastener 179 isspecifically intended to travel across the neck and span the fracture.This arrangement, together with the use of locking fasteners, provide anexceptionally robust scaffold for supporting the articular surface ofthe proximal radius. In addition, fasteners 159, 169 and 189 extenddiametrically across the diaphysis of the radius bone. These fastenerscarry the load on the plate back to the diaphysis. Fourth arm 150 andfifth arm 160 optionally can be removed, by reverse bending, if notrequired to support the fracture.

While it is not necessary to include all of the above described featuresin the radial plate 100, all such features are included in a preferredembodiment, as such are considered optimum for configuring the plate tothe proximal radius and for supporting fractures thereat.

Bone Plates for the Lateral and Medial Surfaces of the Distal Humerus

FIGS. 9, 10 and 11 show a bone plate for the lateral surface of thedistal humerus. FIG. 9 is a perspective view of a top surface 208 and ananterior edge 248 of a lateral plate 200 for the distal humerus. FIG. 10is a perspective view of the top surface 208 and a posterior edge 250 oflateral plate 200. FIG. 11 is a perspective view of a bottom surface 210of lateral plate 200. Lateral plate 200 includes a body 206 having adistal end 204, a proximal end 202 and a curvilinear axis 209. Thebottom surface 210 at the distal end 204 is concave along thelongitudinal axis 209, while the remainder of the bottom surface is flator convex long the axis. This permits the distal end 204 to seat closeto the lateral epicondyle 26. A first locating foot 242 and a secondlocating foot 244 extend downwardly (toward the bone surface) fromposterior edge 250 and are provided to assist the surgeon duringplacement of lateral plate 200 onto the bone surface by seating on thebone contours of the posterior surface of the distal humerus. Eachlocating foot 242, 244 has a size (bone contacting surface area)preferably approximating the cross-sectional area of a screw hole (220,222, 224, 226, 228, 230, 232, discussed below).

Lateral plate 200 may also include a first segment 212 extending alongcurvilinear axis 209 from distal end 204 of body 206. First segment 212is attached to distal end 204 by a first bendable bridge element 216,which is offset from curvilinear axis 209 such that it forms acontinuation of the posterior edge 250. Lateral plate 200 may furtherinclude a second segment 214 extending along curvilinear axis 209 andattached to first segment 212 by a second bendable bridge element 218,which also is offset from curvilinear axis 209 and forms a continuationof the posterior edge 250. First and second bendable bridge elements216, 218 form a bendable spine 231 that is reconfigurable during thesurgical procedure, as will be described. The bendable bridge elements216, 218 are defined along the posterior edge 250, rather than centrallylocated, so that when the patient's elbow is placed on a surface, thearea of the plate which loads against the surface is smooth so as toprevent discomfort to the patient. The distal end 204 of body 206,segment 212, and segment 214 each have squared off ends opposite thebendable spine 231. This facilitates use of bending tools 1600A, 1600B,as described below with respect to FIGS. 46-48C.

In the present embodiment, body 206 includes first, second, third,fourth, and fifth holes 220, 222, 224, 226 and 228, respectively, eachfor receiving a fastener. Each of first and second segments, 212 and214, also include a hole 230 and 232, respectively, for receiving afastener. Holes 220, 222, 224, 226, 228, 230 and 232 preferably have atapered thread for receiving any one of multidirectional locking screw1000, fixed-angle locking screw 1100, and multidirectional compressionscrew 1200, and also for receiving either one of first drill guide 1400(FIG. 41) or second drill guide 1500 (FIG. 43). As described for radialplate 100, the use of preassembled drill guides in segments 212 and 214allows the surgeon to use bending tools to reconfigure bendable spine231, as will be described for FIGS. 47 and 48. The use of preassembleddrill guides in holes 220, 222, 224, 226, 228 permits additionalreconfiguration of the plate. The use of preassembled drill guides inany of the threaded holes aids in drilling through the bone in alignmentwith the holes in the plate, as well as temporary fixation of the plateto the bone with K-wires, as described below.

Lateral plate 200 may also include two elongated slots 234, 236 locatedin body portion 206 for receiving a compression screw such as either ofstandard compression screw 700 (FIG. 27) or multidirectional compressionscrew 1200 (FIG. 40). As it is well-known in the art, the compressionfastener may be inserted into slots 234, 236 to dynamically compresslateral plate 200 in the vertical and axial directions to facilitatefracture reduction prior to insertion of the remaining fasteners.

Lateral plate 200 may also include cut-outs 246 a, 246 b on each side ofelongated slot 234 and cut-outs 247 a, 247 b on each side of elongatedslot 236 in order to (i) provide clearance at the edges of the plate forfasteners that are angled toward the posterior of the bone in order toattain maximum purchase on the bone, (ii) to normalize the stiffness onboth sides of the slot, (iii) to reduce the stiffness of the plate at aslot to permit bending through a slot via the use of drill guidesinserted into threaded holes on either side of a slot and appropriatebending tools, and/or (iv) to make that portion of body 206 less stiffthan the adjoining portions, thereby allowing slight reconfiguration ofbody portion 206 to more closely match the shape of the bone surfaceupon insertion of a compression fastener. Increased clearance ispreferred at the posterior edge 248 of the plate adjacent slots 234,236, as this is the side toward which the fasteners are angled for bonepurchase. It is further preferred that the elongated slots 234, 236 becentered off-axis from longitudinal axis 209, but oriented parallelthereto so as to define two rails of different width connecting theportions of the plate on either side of the slot 234. With respect toslot 234 (slot 236 is similarly structured), larger cut-out 246 a isprovided in association with larger rail 249 a, and smaller cut-out 246b is provided in association with smaller rail 249 b. This configurationprovides additional clearance at the posterior edge for screworientation into cortical bone. The area of the cut-outs 246 a, 246 bare preferably dimensioned such that each of the rails 249 a, 249 b hassubstantially equal stiffness (preferably within ten percent of eachother, and more preferably within five percent of each other). However,the overall stiffness of the plate body in the region of the slot isreduced by the cut-outs to facilitate reconfiguration of the plate.

Lateral plate 200 may also include an hourglass-shaped openings 238, 239near distal end 204. Opening 238 reduces the stiffness of the platebetween holes 224, 226 to allow distal end 204 to be reconfigurableusing bending tools such as shown in FIG. 5 without a discontinuation ofposterior and anterior edges 248, 250. The opposing ends of opening 238may also be configured to guide a conventional K-wire to capture andhold bone fragments while adjacent fasteners are inserted. Opening 239functions between holes 226 and 228 in the same manner as opening 238.Similarly, each of the spacings 213, 215 between segments 212 and 214and between segment 212 and distal end 204, respectively, may also beconfigured to guide a conventional K-wire. To that end, spacings 213,215 may be shaped to retain a guidewire between a narrower centralportion 213 a, 215 a and a larger closed end 213 b, 215 b (throat) (FIG.9). Lateral plate 200 (as well as medial plate 300 or posterolateralplate 400) may optionally include one or more multifunctional hole thatmay be used to guide a conventional K-wire and as an attachment pointfor a suture. Such a multifunctional hole is described in detail in U.S.Pub. No. 20070270849A1, which is hereby incorporated by reference hereinin its entirety.

It is an important feature of the lateral plate that it is, overall,progressively stiffer from the distal end to the proximal end,corresponding to the loads experienced at respective portions of theplate. The lateral plate is most preferably approximately 2 mm thickalong its length and used in conjunction with a medial plate 300,described below, of substantially the same thickness.

While it is not necessary to include all of the above described featuresin the lateral plate 200, all such features can be included in anembodiment, and the inclusion of the described features is consideredoptimum for configuring the plate to the lateral surface of the distalhumerus and for supporting fractures thereat.

FIG. 12 is a perspective view of a top surface 398 of a bone plate 300for the medial surface of the distal humerus, also called a medial plate300. FIG. 13 is a perspective view of a bottom surface 310 medial plate300. Medial plate 300 is similar to lateral plate 200, with variationsin shape, size, and hole configuration.

Medial plate 300 includes a body 306 having a proximal end 302, a distalend 304 and a curvilinear axis 309. The bottom surface 310 at the distalend 304 is concave along the curvilinear axis 309, while the remainderof the bottom surface is slightly convex or flat along the axis. Thispermits the distal end 304 to seat close to the medial epicondyle 24.Medial plate 300 also includes a first segment 336 extending alongcurvilinear axis 309 from distal end 304 of body 306. First segment 336is attached to distal end 304 by a first bendable bridge element 340,which is offset from curvilinear axis 309, such that it forms acontinuation of a posterior edge 350. Medial plate 300 may furtherinclude a second segment 338 extending along curvilinear axis 309 andattached to first segment 336 by a second bendable bridge element 342,which also is offset from curvilinear axis 309 and forms a continuationof the posterior edge 350. First and second bridge elements 340, 350preferably have a portion of reduced thickness (transverse to the axis309 and width of the plate, and seen in FIG. 13), that facilitatesbending thereof. First and second bendable bridge elements 340, 342 forma bendable spine 331 that is reconfigurable during the surgicalprocedure, as will be described for FIGS. 47 and 48. The distal end 304of the body 306, segment 336 and segment 338 each have squared off endsopposite the bendable spine 331. This facilitates use of bending tools1600A, 1600B, as described below with respect to FIGS. 46-48C. Thebendable bridge elements 340, 342 are defined along the posterior edge350, rather than centrally located, so that when the patient's elbow isplaced on a surface, the area of the plate which loads against thesurface is smooth so as to prevent discomfort to the patient.

As shown in FIG. 12, body 306 includes first, second, third, fourth andfifth holes, 312, 314, 316, 318 and 320, respectively, each forreceiving a fastener. Each of the first and second segments 336 and 338also include a hole 322 and 324, respectively, for receiving a fastener.Holes 312, 314, 316, 318, 320, 336 and 338 are preferably configuredwith a tapered thread to receive any one of multidirectional lockingscrew 1000, fixed-angle locking screw 1100 or multidirectionalcompression screw 1200, and either one of first drill guide 1400 andsecond drill guide 1500. As described for radial plate 100, the use ofpreassembled drill guides in segments 322 and 324 allows the surgeon touse bending tools such as shown in FIGS. 46 and 47 to reconfigurebendable spine 331.

Medial plate 300 may also include a first elongated slot 326, a secondelongated slot 328, and a third elongate slot 329, each located in bodyportion 306 for receiving either one of standard compression screw 700(FIG. 27) and multidirectional compression screw 1200 (FIG. 40) tofacilitate the dynamic compression of medial plate 300 to the bone priorto insertion of the remaining fasteners.

Medial plate 300 may also include a cut-out 333 on each side of each ofelongated slots 326, 328 and 329 in order to make that portion of body306 less stiff than the adjoining portions, thereby allowing slightreconfiguration of body portion 306 to more closely match the shape ofthe bone surface. For example, (i) drill guides assembled in threadedholes 312, 314, 316, 318, 320 on opposite sides of slots 326, 328, 329may be subject to force with tools to reconfigure the plate about theslot, and (ii) standard compression screw 700 may be inserted into eachof slots 326 and 328 and tightened in order to draw bottom surface 310against the bone, prior to insertion of the remaining fasteners.

It is an important feature of the medial plate that it is, overall,progressively stiffer from the distal end to the proximal end,corresponding to the loads experienced at respective portions of theplate.

While it is not necessary to include all of the above described featuresin the medial plate 300, all such features can be included in anembodiment, and the inclusion of the described features is consideredoptimum for configuring the plate to the medial surface of the distalhumerus and for supporting fractures thereat.

FIG. 14 is a posterior, transparent view of the distal humerus, showinglateral plate 200 attached near the lateral epicondyle 26 and medialplate 300 attached near the medial epicondyle 24 by a plurality offasteners. Depending on the type and severity of the fracture, one orboth of lateral plate 200 and medial plate 300 may be attached to thedistal humeral during the surgical procedure. The lateral and medialplates 200, 300 are located on the humeral bone in a “parallel”configuration, with the plates provided on opposite lateral and medialportions of the bone. The lateral and medial plates 200, 300 arepreferably provided in different lengths so that the respective proximalends 202, 302 of the plates end at different locations on the bone andthereby reduce stress concentrations on the bone. As shown, acombination of cancellous (coarsely threaded) and cortical (finelythreaded) fasteners may be used. Lateral plate 200 and medial plate 300may be provided with fastener holes configured for receiving fixed-anglelocking screw 1100, such that the trajectories of the screws areunlikely to intersect. If necessary, however, the surgeon may alsoattach lateral plate 200 and medial plate 300 to the distal humerususing either of multidirectional locking screw 1000 and multidirectionalcompression screw 1200. Using conventional, intraoperative fluoroscopicx-ray techniques, the surgeon may insert the fasteners with a desiredtrajectory to avoid other fasteners and fracture lines and to capturebone fragments.

Bone Plate for the Posterolateral Surface of the Distal Humerus

FIG. 15A is a top perspective view and FIG. 15B is a bottom perspectiveview of a posterolateral plate 400 for the distal humerus.Posterolateral plate 400 includes a body 406 having a proximal end 402,a distal end 404 and a curvilinear, longitudinal axis 403 extendingtherebetween. A first arm 410 and a second arm 420 extend from distalend 404 on opposing sides of axis 403, thereby forming a Y-shape. Athird arm 430 extends from the body 406 adjacent distal end transverselyaway from axis 403. Alternatively, third 430 can extend from second arm420. First arm 410 has a first arm axis 413, second arm 420 has a secondarm axis 423 and third arm 430 has a third arm axis 433. Third arm axis433 is transverse to axis 403, such that third arm 430 may wrappartially around the lateral side of the distal humerus.

Still referring to FIGS. 15A and 15B, first arm 410 includes a firstring element 412 having a hole 414 and is attached to proximal end 404of body 406 by a first bendable bridge element 416. Second arm 420includes a second ring element 422 having a hole 424 and attached todistal end 404 by a second bendable bridge element 426. Third arm 430includes a third ring element 432 having a hole 434 and attached to body406 by a third bendable bridge element 436. Body 406 includes holes 440,442, 444, 446 and 448, and an elongated slot 450, each of which may belocated along longitudinal axis 403. Each of holes 440, 442, 444, 446,448, 414, 424 and 434 may be configured with an internal taper threadfor receiving any one of multidirectional locking screw 1000,fixed-angle locking screw 1100, or multidirectional compression screw1200 shown in FIGS. 32, 30 and 35, respectively. Slot 450 may beconfigured to receive either one of standard compression screw 700 andmultidirectional compression screw 1200 shown in FIGS. 27 and 40,respectively. Slot 450 includes cutouts 452 on either side thereof toreduce the stiffness of the body 406 at the slot.

Posterolateral plate 400 also includes two hourglass-shaped openings454, 456 at the distal side of slot 450. Each opening 454, 456 issubstantially similar in design to hourglass shaped slot 238 of lateralplate 200. Such opening 454, 456 reduce the stiffness of the platebetween holes to allow the distal end 404 of the body 406 to bereconfigurable using bending tools such as shown in FIG. 5 without adiscontinuation of the anterior and posterior edges of the plate as wellas retain K-wires for temporary fixation.

FIG. 16 is top perspective view of posterolateral plate 400, shownpreassembled with a plurality of first drill guides 1400 (FIG. 41) andsecond drill guides 1500 (FIG. 43). As described for radial plate 100 inFIG. 5, bending tools 2160, 2180 may be used to reconfigureposterolateral plate 400 while the plate is positioned on the bonesurface. In this way, the surgeon may closely match the shape ofposterolateral plate 400 to the bone surface and redirect thetrajectories of the fasteners to capture bone fragments and avoidfracture lines and other fasteners. Slot 450 is longer than aconventional compression screw slot to reduce the axial torsionalstiffness thereat. In this manner, guides in holes 444 and 446 may beused to impart a torque along the axis of the plate to result in antwist to enhance conformation of the plate to the bone, as well asimpart a bending force across hourglass-shaped opening 454.Additionally, guides in holes 446 and 448 can be used to impart abending force across hourglass-shaped opening 456. Third arm 430 iscoupled to the body portion 406 near hole 446; thus the plate 400 ishighly adjustable in shape on either side of the location at which thethird arm 430 is attached. Guides in holes 413, 423, 433, in conjunctionwith appropriate bending tools, can be used to impart bending forces toreconfigure the orientation of the arms 410, 420, 430 to approximate thering elements 412, 422, 432 to the bone and redirect the axes throughthe holes, if necessary. Particularly, arm 430 can be reconfigured toabout the humerus to squeeze the lateral condyle 26 and provide lagging.

FIG. 17 is top perspective view of posterolateral plate 400, shown witha plurality of fasteners 441, 443, 445, 447, 449, 415, 425 and 435 fullyinserted and locked into holes 440, 442, 444, 446, 448, 414, 424 and434, respectively. Fastener 451 is fully inserted into slot 450. Each offasteners 415, 425 and 435, 445 has an axis 419, 429, 439, and 461,respectively, wherein axes 419, 429 and 461 are approximately parallel,and axis 439 extends transverse to axes 419, 429 and 461 and betweenaxes 419, 421 and axis 461.

As shown in FIG. 15B, each of first ring element 410, second ringelement 420 and third ring element 430 have a bottom surface 411, 421and 431, respectively, each of which is configured to conform to thebone surface, but is approximately planar. In order to provide theappropriate fastener trajectory, the thickness of first and second ringelements 412, 422 is greater at a distal region than at a relativelyproximal region where the ring elements are coupled to the first andsecond bridge elements 416, 426. As shown in FIGS. 15B and 17, each ofaxes 419, 429 and 439 is preferably non-perpendicular to bottom surfaces411, 421 and 431, respectively, such that the trajectories of fasteners419, 429 and 439, are optimized for capturing bone fragments andsupporting the subchondral surface of the distal humerus. The load fromfasteners 415, 425, 435 and 439 is transferred along the plate and tofasteners 441, 443, and 445, where the load is transferred back to theload bearing diaphysis of the humerus.

While it is not necessary to include all of the above described featuresin the posterolateral plate 400, all such features can be included in anembodiment, and the inclusion of the described features is consideredoptimum for configuring the plate to the lateral surface of the distalhumerus and for supporting fractures thereat.

FIG. 18 is a wire frame drawing of the posterolateral plate 400 attachedto the posterolateral surface of the distal humerus. FIG. 18A is atransparent view showing the medial and posterolateral plates 300, 400together attached to the distal humerus in a “perpendicular” approach.In this configuration, the medial plate is provided at the medial sideof the distal humerus bone while the posterolateral plate is provided atthe posterolateral portion of the distal humeral bone. In theperpendicular configuration, loading of the plate is in the direction ofthe height of the plate. Therefore, the posterolateral plate issubstantially thicker than the medial plate. By way of example, theposterolateral plate is preferably approximately 3.5 mm thick; i.e.,1.75 times the thicker than the medial plate). Fracture fixation usingthe perpendicular approach with the medial and posterior plates providessubstantially the same stiffness as the parallel approach with thelateral and medial plates 200, 300.

Bone Plate for the Coronoid of the Proximal Ulna

FIG. 19 is a perspective view of a top surface 501 of a bone plate 500,also called a coronoid plate 500, for the coronoid of the proximal ulna.The coronoid plate 500 is specifically designed to seat on a ridge ofthe bone. FIG. 20 is a perspective view of a bottom surface 503 ofcoronoid plate 500. FIG. 21 shows the coronoid plate 500 attached to theproximal ulna. Coronoid plate 500 includes a central ring element 502containing a hole 505 for receiving a fastener for attachment to thebone. Coronoid plate also includes a first arm 510 extending distallyfrom central ring element 502. In this embodiment, first arm 510includes a first, a second and a third ring element, 512, 514 and 516,respectively, interconnected in series to central ring element 502 by afirst, a second and a third bendable bridge element, 511, 518 and 519,respectively, and having a first, a second and a third hole, 513, 515and 517, respectively. The lower surface of ring elements 512, 514, 516is concave in the medial-lateral direction. Referring to FIGS. 1, 2 and19-22, this forces the plate to align along the coronoid ridge 36 sothat fasteners 560, 562, 564 inserted through the holes 513, 515, 517 infirst, second and third ring elements 512, 514, 516 will be directedtoward surface 38 below the olecranon 34 and lateral to the ridge 40extending therefrom. This surface 38 has a maximum of soft tissue in thearea to cover the ends of any exiting fasteners.

Coronoid plate 500 may also include a second arm 520 extending mediallyfrom central ring element 502. Second arm 520 may include a fourth ringelement 522 with a fourth hole 523 connected to central ring element 502by a fourth bendable bridge element 521. Second arm 520 may also includea first buttress element 524 (preferably in the form of a tab or paddle)connected to fourth ring element 522 by a bendable web element 525,thereby extending second arm 520 medially. The upper and lower surfacesof the first buttress element 524 is oriented at an oblique angle (shownby corresponding axis D) relative to the central axis 528 through fourthhole 523 in the fourth ring element 522. First buttress element 524provides cantilevered support without having to drill a hole, as thesurgical approach does not afford suitable access to drill a hole andinsert a fastener.

Coronoid plate 500 may also include a third arm 530 extending laterallyfrom central ring element 502. Third arm 530 may include a fifth ringelement 532 with a fifth hole 533 connected to central ring element 502by a fifth bendable bridge element 531.

Coronoid plate 500 may also include a second buttress element 526connected to central ring element 502 by a second bendable web element527 and extending proximally. Second buttress element 526 providessupport for the sublime tubercle which is too small a fragment fordrilling. The relative shapes and sizes of buttress element 526 and webelement 527 also permit the structure to be used as an attachmentlocation for suture, which can be wrapped around the web element 527 andsewn into a ligament.

Each of holes 513, 515, 517, 523 and 533 is preferably configured with atapered thread to receive any one of multidirectional locking screw1000, fixed-angle locking screw 1100, and multidirectional compressionscrew 1200. Holes 513, 515, 517, 523 and 533 also may be configured tobe preassembled with either one of first drill guide 1400 and seconddrill guide 1500. As described for radial plate 100 in FIG. 5, bendingtools 2160, 2180 may be used to reconfigure coronoid plate 500 while theplate is positioned on the bone surface. In this way, the surgeon mayclosely match the shape of coronoid plate 500 to the bone surface andalso redirect the trajectories of the fasteners to capture bonefragments and to avoid fracture lines and other fasteners.

Bendable web elements 525, 527 may be reconfigured using conventionalsurgical pliers or the like to position buttress elements 524 and 526against the bone surface, thereby providing additional support to thehealing bone fragments.

Each of bendable web elements 525, 527 and bendable bridge elements 511,518, 519, 521 and 531 may be easily broken by repeated reverse bendingthrough a significantly large angular range using conventional surgicalpliers or the like. The surgeon may easily create the break, such thatthe broken edge of the implant is directed towards the bone surface inorder to prevent injury to surrounding soft tissue. In this way, thesurgeon may customize coronoid plate 500 according to the anatomy of thepatient.

As shown in FIG. 20, arms 510, 520 and 530, and bottom surface 503 undereach of ring elements 512, 514, 516, 522 and 532 may be shaped toclosely match the contour of the bone at the coronoid of most patients,although other shapes are possible.

FIG. 22 is a perspective, transparent view of coronoid plate 500attached to coronoid 16 of the proximal ulna. As seen in the figure,four ring elements 502, 512, 514, 516 forming a backbone of the platesit on a ridge of the bone. This configuration permits relative easyaccess to plate placement by the surgeon and also allows the plate to bekept away from ligament insertion points and to facilitate. A pluralityof bicortical fasteners may be used to create a stable construct forholding bone fragments in healing alignment and sharing the loadtransferred through the joint. The buttress elements 524, 526 providethe plate 500 with structure that permit fracture support even thoughthere is not commonly ready access to that portion of the bone and wheremaintaining low profile support is a significant consideration.

The preferred coronoid plate 500 includes a central ring 502 coupled toone arm 532 having a single hole 533, another arm 527 having a singlebuttress 526 and no hole, another arm having a single hole 523 and asingle buttress 524, and another arm having a plurality of holes 513,515, 517 and no buttress. The coronoid plate 500 functions as a buttressto counteract the tendency of the elbow to subluxate while also holdingthe small fragments in healing alignment. While the number of armsextending from central ring element 502, the number of ring elements(and holes) interconnected by the bendable bridge elements in each ofthe arms may vary, and the number of buttresses may vary, the abovedescribed configuration of the coronoid plate 500 is preferred as it isconsidered to be optimum for support of the underlying bone fracture.

Bone Plate for the Olecranon

FIGS. 23A through 25 are views of a bone plate 600 for the olecranon ofthe proximal ulna. FIG. 23A is a top perspective view and FIG. 23B is abottom perspective view of the olecranon plate 600, which includes aproximal end 604, a distal end 602 and a longitudinal axis 612 extendingtherebetween. Olecranon plate 600 includes a body portion 606, a headportion 610 near proximal end 604 and a neck portion 608 connecting bodyand head portions, 606 and 610. Neck portion 608 is transverselynarrower than either of body portion 606 and head portion 610 andincreases in thickness toward the head portion. Head portion 608includes a head axis 614 that is transverse to longitudinal axis 612 ofbody portion 606. Olecranon plate 600 has a top surface 601, a bottomsurface 603, a medial edge 605 and a lateral edge 607.

Body portion 606 may include a plurality of holes 622, 624, 626, 628 forreceiving bone fasteners. Body portion 606 may also include at least oneslot 634 for receiving a bone fastener and for facilitating the dynamiccompression of the fractured bone, as described previously for lateralplate 200 of FIG. 9. Holes 622, 624, 626 and 628 and slot 634 aregenerally aligned along longitudinal axis 612 and are preferablyconfigured with an internal tapered thread to receive any one offixed-angle locking screw 1100, multidirectional locking screw 1000 andmultidirectional compression screw 1200.

Head portion 610 may include at least two holes 630 and 632 aligned onthe transverse axis and offset on opposite sides of longitudinal axis612. Holes 630, 632 may be configured for receiving any one ofmultidirectional locking screw 1000, fixed angle locking screw 1100, andmultidirectional compression screw 1200 of FIGS. 30, 32 and 35,respectively. The axes of holes 630 and 632 are preferably oriented todirect two fixed angle locking screws in slightly divergent trajectoriesinto the olecranon and also to be provide space for the ‘home run screw’650 discussed below.

Olecranon plate 600 may further include a first arm 616 extendingmedially from medial edge 605 of neck portion 608. First arm 616includes a first ring element 636 having a first hole 637 for receivinga bone fastener and is attached to neck portion 608 by a first bendablebridge element 642.

Olecranon plate 600 may further include a second arm 618 extendinglaterally opposite of first arm 616 from a lateral edge 607 of neckportion 608. Second arm 618 includes a second ring element 638 having asecond hole 639 for receiving a bone fastener, and is attached to neckportion 608 by a second bendable bridge element 644.

Olecranon plate 600 may further include a third arm 620 extendingproximally from head portion 610 and centered on longitudinal axis 612.Third arm 620 includes a third ring element 640 attached to head portion610 by a third bendable bridge element 645. The third ring element has athird hole 641 for receiving a bone fastener.

Each of holes 637, 639 and 641 of first, second and third arms, 636, 638and 640, respectively, may be configured to receive any one ofmultidirectional locking screw 1000, fixed angle locking screw 1100, andmultidirectional compression screw 1200.

Referring to FIG. 23B, olecranon plate 600 may also include at least onealignment foot 656 extending downwardly (towards the bone surface) fromedge 607 of body 606. Foot 656 aligns the plate relative to ananatomical ridge on the bone. In fact, the foot 656 permits the plate tobe aligned blindly (particularly when the surgical wound cannot beopened to expose the entire bone surface) and to maintain platealignment relative to anatomical landmarks to ensure proper trajectoryof bone screws.

FIG. 23C is a bottom perspective view of olecranon plate 600, shown witha plurality of fasteners fully inserted. Notably, second arm 618 isshown without a fastener inserted. Olecranon plate 600 may be used oneither one of the right and left arms of the patient, but it isgenerally not necessary, for a given fracture, to insert a fastener intoeach of the first and second arms, 616 and 618, in order to form theneeded supporting construct in the bone. Therefore, the surgeon mayselect one of the first and second arms, 616 and 618, to use with afastener. Optionally, the surgeon may use bending tools 2160, 2180 (FIG.5) to break off the unused one of first and second arms 616, 618.

As shown in FIG. 23C, an extra long fastener 650, referred to as a “homerun screw”, may be inserted into third arm 620 to capture the fracturedbone fragments and to provide subchondral support. An axis 651 offastener 650 is generally directed between a pair of axes, 653 and 655,of fasteners 652 and 654, respectively, and preferably at approximately20° to 45° relative to the longitudinal axis 612 of the plate.

As for the other bone plates described herein and shown in FIG. 24, eachof the holes in olecranon plate 600 may be preassembled with either offirst drill guide 1400 (FIG. 41) and second drill guide 1500 (FIG. 43)to facilitate fastener hole drilling and, if desired, reconfiguration ofolecranon plate 600. Referring to FIGS. 23B and 24, third arm 620 iseasily reconfigurable in the x-z plane to support the olecranon, suchthat the trajectory of a fastener inserted into hole 641 passes betweenthe trajectories of fasteners inserted into holes 630 and 632.

FIG. 25 is a medial side, transparent view of the proximal ulna witholecranon plate 600 attached to olecranon 12. In this example, afastener is not shown inserted into second arm 618 (hidden), for thereasons already described. Fastener 650 passes between fasteners 652,654 and through the subchondral bone of the proximal ulna, therebycapturing the fractured bone fragments and allowing olecranon plate 600to share the forces transmitted through olecranon 12.

FIG. 26 is a top perspective view of a large olecranon plate 800, whichis an alternate embodiment of olecranon plate 600. Olecranon plate 800is configured for larger patients and differs from olecranon plate 600primarily in overall size and number of holes and slots for receivingfasteners. Olecranon plate 800 has a third arm 820 that includes adouble-ring element 822 with rings 840, 860 attached to a proximal end804 by a third bendable bridge element 846. Each ring of the double-ringelement 822 is attached to the other by two curved segments 862, 864that permit rings 840, 860 to be closely spaced, but provide a relativelarge length for relative bending. Double-ring element 822 provides forthe insertion of two parallel fasteners (not shown) rather than thesingle fastener 650 shown in FIG. 23C, or two angled fasteners if guidesare inserted into the rings 840, 860 and the axes thereof are bentrelative to each other. This permits the large olecranon plate 800 to beconfigured by the surgeon to conform to unpredictable portions of theolecranon. In addition, two slots 834, 835 are provided. Slot 835 islonger than slot 834.

According to one method for implanting plate 800, two fasteners areinserted through the proximal olecranon at holes 830 and 832. Then afastener is inserted through shorter slot 834 to reduce the fracture viadynamic compression. The third arm is then bent down, as necessary, toconform to the olecranon and the home run screws are inserted throughholes 840 and 860. An additional fastener is optionally inserted throughslot 835. The first or second arm 816, 818 and other threaded holes 822,824, 825, 826, 828 are then provided with fasteners to complete thefixation and load transfer back to the diaphysis.

The embodiments of the olecranon plate shown are structured, and theholes thereof oriented, such that fasteners inserted therein and coupledthereto properly transfer the high forces of the triceps muscle to moredistal areas of the ulna. While it is not necessary to include all ofthe above described features in the olecranon plates 600, 800, suchfeatures are included in the preferred embodiments, as such areconsidered optimum for configuring the olecranon plates 600, 800 to theolecranon of the proximal ulna for supporting fractures thereat.

Fasteners

FIGS. 27 through 40 show four embodiments of bone fasteners (alsoreferred to as screws and pegs) that may be used with radial plate 100,lateral plate 200, medial plate 300, posterolateral plate 400, coronoidplate 500 and olecranon plates 600, 800. The fasteners are describedgenerically since the actual dimensions of each fastener may varydepending on the bone plate and the type of fracture. The type of bodythread for each screw may be either one of a cortical thread and acancellous thread and extend along at least a portion of the screw body.For the fastener embodiments shown that include threaded heads forlocking into a threaded hole of the bone plate, the fastener body may beeither one of a threaded body or a smooth body.

FIG. 28 is a side view and FIG. 27 is a head end view of a standardcompression screw 700 having a head 702 and a threaded body 704. Head702 has a spherically convex bottom portion 708 that is specificallyconfigured to seat into a spherically concave plate hole to compress thebone plate against the bone, although it is possible to use screw 700with other types of plate holes. As is well known in the art, screw 700may also be used in an elongated slot having a spherically concaveperipheral wall for dynamic compression, in which the screw providesboth a vertically directed force and an axially directed force to thebone plate to aid in the fracture reduction. Head 702 includes a hexdrive recess 706, although other recess configurations for other typesof drivers is possible. Screw 700 may be formed from a titanium alloy oranother metal.

FIG. 29 is a head end view, FIG. 30 is a side view, and FIG. 31 is adetailed view of a multidirectional locking screw 1000 fully insertedinto a bone plate 1008 having a tapered threaded hole 1009. Screw 1000includes a threaded body 1004 and a head 1002 having a square driverecess 1006. Screw 1000 may be locked into plate 1008, such that a screwaxis 1010 forms an angle 1015 in the range of 0-15 degrees with a holeaxis 1011. Screw 1000 may be formed from a cobalt-chrome alloy that issignificantly harder than the plate material, which may be a titaniumalloy. Such a multidirectional locking screw is described in detail inU.S. Pub. No. 20070088360A1, which is hereby incorporated by referenceherein in its entirety.

FIG. 32 is a perspective view, FIG. 33 is a head end view and FIG. 34 isa detailed cross-sectional view of a fixed angle locking screw 1100,which includes a threaded body 1104 and a tapered threaded head 1102having a hexabular recess 1106. Screw 1100 may be inserted and lockedinto a tapered, threaded hole of a bone plate at a fixed anglepredetermined by the hole thread axis.

FIGS. 35 through 38 are views of a multidirectional compression fastener1200, also called screw 1200. FIG. 35 is a perspective view and FIG. 36is a detailed view of the proximal portion of screw 1200, which includesa body 1204 having a thread 1206 and a distal tip 1214. Screw 1200further includes a head 1202 having a proximal face 1208 with a squaredrive recess 1208, although other drive recess configurations arepossible. Head 1202 includes a smooth, frustoconical portion 1212 havinga small diameter end 1240 (indicated by D1) attached to body 1204 and alarge diameter end 1242 (indicated by D2) forming a peripheral edge 1206of proximal face 1208. Frustoconical portion 1212 has an included angle1244 (indicated by A) centered on a screw axis 1220. Peripheral edge1206 may have an external radius 1242 (indicated by R). Thread 1216 maybe one of a cancellous thread and a cortical thread and may be formedinto at least a portion of the length of body 1204.

FIGS. 37 and 38 are detailed, cross-sectional views of screw 1200inserted into a tapered threaded hole 1232 of a bone plate 1234. Firstreferring to FIG. 37, tapered threaded hole 1232 has an included angle1252 (indicated by B) centered on hole axis 1230. Screw axis 1220 ofscrew 1200 and hole axis 1230 form an insertion angle 1250 (indicated byC). In this embodiment, insertion angle 1250 may range from 0-15 degreesand is contained by a plane containing hole axis 1230, such that all thepossible orientations of screw axis 1220, when fully inserted into hole1232, define a 30 degree conical volume extending from the bottom ofplate 1234. When screw 1200 is fully inserted into hole 1232,frustoconical portion 1212 compresses against hole 1232, but is toolarge to pass completely through hole 1232. A maximum protrusion height1254 (indicated by H1) extends above the top surface of plate 1234.

FIG. 38 shows screw axis 120 and hole axis 1230 to be colinear, suchthat insertion angle is zero. A minimum protrusion height 1256(indicated by H2) extends above the top surface of plate 1234. In thisembodiment, H2 is less than H1, and each of H1 and H2 have an acceptablylow profile, such that head 1202 is atraumatic to the surrounding softtissue.

As will be appreciated by those skilled in the art, the present systemdescribed herein provides to a surgeon the advantageous option to useany one of a standard compression screw (screw 700 of FIG. 28), a fixedangle locking screw (screw 1100 of FIG. 33), a multidirectionalcompression screw (screw 1200 of FIG. 35) and a multidirectional lockingscrew (screw 1000 of FIG. 30) in the same tapered threaded hole, whichis included in each the bone plates described herein. In addition, eachof screws 700, 1100, 1200 and 1000 are insertable into the taperedthreaded hole, such that the screw head is minimally proud relative tothe top surface of the bone plate, thereby minimizing patient discomfortand complications due to soft tissue irritation.

FIG. 39 is a perspective view of a screw head adaptor 1300 provided foruse with multidirectional compression screw 1200 of FIG. 35. FIG. 40shows how adaptor 1300 may be assembled to head 1202 of screw 1200 andthen used in a similar manner as standard compression screw 700 of FIG.27. Adaptor 1300 includes a spherically convex bottom portion 1302 and arounded upper portion 1304. Bottom portion 1302 and upper portion 1304form a circular peripheral edge 1312 and together resemble the profileof a standard compression screw head. Adaptor 1300 further includes abore 1310 having a smooth conical surface 1306 against which head 1202of screw 1200 is received, such that head 1202 is flush with top portion1304 of adaptor 1300 when fully inserted.

The screw head adaptor 1300 preferably includes means for engaging thehead 1202 of the screw 1200 such that the screw 1200 and adaptor 1300are assembled to each other to be handled together as a unit during asurgical procedure. According to a preferred embodiment, retaining tabs1340 are circumferentially displaced about the upper portion of bore1310. As the screw head 1202 is forced through the adaptor 1300 duringassembly, the head 1202 deflects the tabs 1340 radially outward toprovide sufficient access for the head 1202 to be received against theconical surface 1306 of the bore 1310, and the tabs 1340 then snap backover the head 1202 to lock the head relative to the adaptor 1300.

Adaptor 1300 and screw 1200 may be used in together as a unit in a platehole having a spherically concave seating surface to compress the boneplate against the bone. Alternatively, as shown in FIG. 40, adaptor 1300and screw 1200 may be used in together as a unit, in a compression slot1235 of a bone plate for dynamically compressing the plate to the bone(in the vertical and axial directions) to assist in fracture reduction.(FIG. 40 may represent both a cross sectional view of a plate hole and atransverse sectional view of a compression slot.) Compression slot 1235may have a spherically concave, inner cam surface 1233 that engages withbottom surface 1302 of adaptor 1300 to drive bone plate 1232 in adesired direction as screw 1200 is screwed into the bone, such as forfurther reducing the bone fracture. Screw 1200 may be insertedmultidirectionally into the bone at an insertion angle 1308 (indicatedby F) defined by screw axis 1220 and slot axis 1330. Insertion angle1308 may range from about 0 to 15 degrees from slot axis 1330.

Adaptor 1300 may be formed from any one of a number of biocompatiblematerials, including titanium, a titanium alloy, a stainless steel and acobalt chrome alloy. Adaptor 1300 may be provide with a smooth, polishedfinish on all surfaces to facilitate multidirectional insertion of screw1200 into the bone and dynamic compression of the bone plate against thebone.

Specialized Instrumentation

FIGS. 41 and 42 are perspective views of a first drill guide 1400 havinga cylindrical body 1402, a proximal end 1406, a distal end 1404. Firstdrill guide 1400 also has a longitudinal bore 1412 with an axis 1414 andsized for guiding a conventional bone drill. A plurality of internaldrive elements 1410 are formed into bore 1412 near proximal end 1406. Inthis embodiment, the plurality of internal drive elements 1410 includesix internal drive elements 1410 for receiving the hexagonally shapeddistal tip of a conventional bone screw driver tool, although otherconfigurations and quantities of internal drive elements 1410 arepossible.

First drill guide 1400 also has a tapered threaded portion 1408 neardistal end 1404 configured for threaded engagement with a taperedthreaded hole in a bone plate, such that axis 1414 is colinear with theaxis of the tapered threaded hole. The bone plate may be provided to thesurgeon with each tapered threaded hole of the bone plate alreadypreassembled with drill guide 1400, so that it is not necessary for thesurgeon or an assistant to attach a drill guide to each hole during theprocedure as is normally done for conventional bone plating systems. Inthis way, the surgeon may quickly drill several bone holes, such thatthe axis of each hole is in perfect alignment with the hole thread axis.The surgeon may then remove the drill guide using the hexagonally tippeddriver and insert a locking bone fastener, such that the threaded headof the locking fastener easily engages with the threaded hole. Due tothe long, cylindrical shape of body 1402, first drill guide 1400 alsomay be used with bending tools to reconfigure the bone plate, as wasalready described for radial plate 100 shown in conjunction with FIGS. 5and 6, and will also be described for lateral plate 200 in conjunctionwith FIGS. 50 and 51. The pre-assembly of a first drill guide to a boneplate is described in co-owned U.S. Pub. No. 20060149250A1, and the useof such drill guide for bending a plate is described in co-owned U.S.Pub. No. 20060161158A1, 20070233111A1, and 20070233112A1, all of whichare hereby incorporated by reference herein in their entireties.

FIGS. 43 and 44 are perspective views of a second drill guide 1500,which includes a bulbous body 1514, a distal end 1504, a proximal end1506 and a distal threaded portion 1502. Second drill guide 1500 alsoincludes a bore 1512 having a longitudinal axis 1516 and sized forguiding a conventional bone drill. A plurality of internal driveelements 1510 are formed into bore 1512 near proximal end 1506 and mayhave an identical configuration as internal drive elements 1410 of firstdrill guide 1400 so that the same hexagonally tipped driver tool may beused, although other configurations and quantities of internal driveelements 1510 are possible.

Distal threaded portion 1502 is configured for threaded engagement witha tapered threaded hole in a bone plate, such that axis 1516 is colinearwith the axis of the tapered threaded hole. As described for first drillguide 1400, a bone plate may be provided to the surgeon with eachtapered threaded hole of the bone plate already preassembled with drillguide 1500, so that it is not necessary for the surgeon or an assistantto attach a drill guide to each hole during the procedure as is normallydone for conventional bone plating systems. The surgeon may then removethe drill guide using the hexagonally tipped driver and insert a lockingbone fastener, such that the threaded head of the locking fastenereasily engages with the threaded hole.

Compared to first drill guide 1400, second drill guide 1500 has a lowprofile once fully inserted into the tapered threaded hole of the boneplate, i.e., second drill guide 1500 is sized for bore 1512 to besufficiently long to guide the bone drill, yet extend minimally abovethe top surface of the bone plate so as to facilitate plate insertionwith minimal removal of tissue and trauma to tissue. The bulbous or“mushroom” shape of body 1514 facilitates handling and manufacture ofsecond drill guide 1500, and is not intended for removable attachment ofthe bending tools shown in FIGS. 5, 6, 46, 47 and 48. By way of example,the body of the first drill guide (i.e., that portion which extendsabove the non-bone contacting surface of plate) has a length of, e.g.,approximately 10 to 15 mm, whereas the corresponding body portion ofsecond drill guide has a length of, e.g., approximately 3 to 7 mm.

Second drill guide 1500 may be used for portions of the bone plate thatare not reconfigurable. As shown in FIG. 45, for example, second drillguide 1500 may be preassembled to lateral plate 200 near proximal end202, a portion of lateral plate 200 that is not reconfigurable. Thelow-profile configuration of second drill guide 1500 allows the surgeonto insert proximal end 202 under retracted soft tissue even with seconddrill guides 1500 attached thereto. This enables the surgeon to make ashorter incision to implant the bone plate than if longer drill guideswere used in proximal end 202. In addition, second drill guide 1500 isminimally obstructive to other instruments used in that portion of thewound site during the procedure.

Another type of bending guide may be used which does not include athroughbore. Such guide may have the external (and optionally theproximal internal) characteristics of either the first or second drillguides, but is used only for bending and not for guiding a drill. Such abending guide may also include an external non-circular cross-section tofacilitate instrument force application and/or removal of the bendingguide from the plate.

FIG. 46 is a perspective view of the distal portion of a bending tool1600 that may be used in conjunction with first drill guide 1400 toreconfigure the bone plate. Bending tool 1600 is an alternate embodimentof bending tools 2160 and 2180 shown in FIGS. 5 and 6. The surgeon mayuse bending tool 1600 for the following: reconfiguring the bone plate tofit the bone more closely; redirecting the trajectory of one or morefasteners; manipulating the bone plate during placement on the bone; andbreaking off an unneeded portion of the bone plate. As described earlierfor bending tools 2160 and 2180, the surgeon may use a pair of bendingtools 1600 to reconfigure the bone plate in situ, i.e., while the plateis positioned on the bone, thereby decreasing the possibility ofplate/bone mismatch and reducing the time of the procedure.

Bending tool 1600 includes a handle 1602 having a longitudinal axis 1603and a distal end effector 1604. Distal end effector 1604 includes aretaining arm 1612 that extends distally and is approximately positionedalong the longitudinal axis 1603. Retaining arm 1612 has a retainingbore 1610 with a bore axis 1618 that is transverse relative tolongitudinal axis 1603. Bore 1610 is sized to receive body 1402 of firstdrill guide 1400, such that the surgeon may removably attach endeffector 1604 to first drill guide 1400 without applying significantforce when bore axis 1618 is colinear with axis 1414 of first drillguide 1400. However, bore 1610 fits slidably over first drill guide1400, such that applying an appropriately directed force to handle 1602induces a force couple on first drill guide 1400 in a plane defined bylongitudinal axis 1603 and bore axis 1618 (plane x-z as indicated by thecoordinate system shown in FIG. 46).

End effector 1604 further includes a first fulcrum 1606 positioned on afirst side 1620 of longitudinal axis 1603, and a second fulcrum 1608positioned on a second side 1622 opposite of first side 1620. Each offirst and second fulcrums 1606 and 1608 is proximally offset from boreaxis 1618 and contained in the plane defined by the longitudinal andbore axes. First fulcrum 1606 may be further offset than second fulcrum1608, as indicated by offset 1623 in FIG. 48. This variation in fulcrumoffset allows bending tool 1600 to be used on bone plates having varyingwidths and, in some situations, to have two options for orientation ofhandle 1402 during use.

FIG. 47 is a perspective view of a pair of bending tools 1600 as theymay be used for reconfiguring lateral plate 200 in the x-y plane, asindicated by the coordinate system shown. A first bending tool 1600A isremovably attached to a drill guide 1400A preassembled to first segment212 of lateral plate 200, such that first side 1620A is in the downwarddirection. A second bending tool 1600B is removably attached to a drillguide 1400B preassembled to distal end 204 of lateral plate 200, suchthat first side 1620B is in the upward direction. First fulcrum 1606Abears against spine 231 of lateral plate 200. Second fulcrum 1608B bearsagainst medial edge 248 of lateral plate 200. When the surgeon appliesequal and same directed forces, indicated by the arrows labeled F1 andF2, in the x-y plane as defined by the coordinate system shown, aleveraging force is applied to spine 231 near first segment 212. In thismanner, the surgeon may reconfigure spine 231 near first segment 212. Asimilar method may be used to reconfigure spine 231 near second segment214. In order to help hold lateral plate in position on the bone, thesurgeon may choose to apply forces F1, F2 after at least one fastener isalready inserted in another portion of the plate.

FIG. 48 is a perspective view of a pair of bending tools 1600 as theymay be used by a surgeon to reconfigure lateral plate 200 in the y-zplane as indicated by the coordinate system shown. First bending tool1600A may be removably attached to drill guide 1400A and second bendingtool 1600B may be removably attached to drill guide 1400B. For thiscase, first fulcrum 1606A does not bear against spine 231 and secondfulcrum 1608B does not bear against medial edge 248, as in the priorcase of FIG. 50. Instead, when the surgeon applies equal and samedirected forces G1 and G2 as indicated by the arrows, a force couple isinduced in each of drill guides 1400A and 1400B, thereby placing atorque on spline 231 to reconfigure that portion of lateral plate 200.

Turning now to FIGS. 49 and 50, alternate embodiments are shown ofbending tools 2600A, 2600B which may be used for the same purpose asbending tools 1600A, 1600B; i.e., in conjunction with first drill guide1400 and a bone plates to reconfigure the bone plate. As shown in FIG.49, bending tool 2600A includes a handle 2602A having a longitudinalaxis 2603A and a distal end effector 2604A. Distal end effector 2604includes a retaining arm 2612A that extends distally and isapproximately positioned along the longitudinal axis 2603A. Retainingarm 2612A has a retaining bore 2610A with a bore axis 2618A that istransverse relative to longitudinal axis 2603A. Bore 2610A is sized toreceive body 1402 of first drill guide 1400, such that the surgeon mayremovably attach end effector 2604A to first drill guide 1400 withoutapplying significant force when bore axis 2618A is colinear with axis1414 of first drill guide 1400. However, bore 2610A fits slidably overfirst drill guide 1400, such that applying an appropriately directedforce to handle 2602A induces a force couple on first drill guide 1400in a plane defined by longitudinal axis 2603A and bore axis 2618A (planex-z as indicated by the coordinate system shown in FIG. 46). Endeffector 2604A further includes a convex fulcrum 2606A proximally offsetfrom bore axis 2618A and contained in the plane defined by thelongitudinal and bore axes 2603A and 2618A. At the opposite end of thehandle 2602A from the end effector 2604A, a bore 2620A is providedcoaxial with the longitudinal axis 2603A. the bore 2620A is sized to beslidable received over drill guide 1400.

Referring to FIG. 50, bending tool 2600B is substantially the same asbending tool 2600A with the following distinctions. The end effector2604B is offset from the handle 2602B by a neck 2622B. The end effectorhas a bore 2610B with bore axis 2618B parallel to, but not coaxial with,the axis of neck 2622B. The fulcrum 2606B is located at the oppositeside of the bore 2610B relative to the handle 2602B and optimally has asmaller offset relative to the bore axis 2618B. Whereas the bendingtools 1600A, 1600B are coupled to a plate with the handles 1602A, 1602Bextending oppositely from the plate, bending tools 2600A, 2600B areconfigured such that the handles 2602A, 2602B apply bending force withthe tools applied to the same side of the plate. This is useful incertain operating situations, primarily due to space considerations. Asshown in FIGS. 51A-51C, this is effected by having the handles 2602A,2602B of the tools 2600A, 2600B at different heights relative to theplate 200 (by inclusion of the neck 2622B on 2600B only) so as toprevent interference between the handles and of a user's fingers aboutthe handles, and by reversing the location of one of the fulcrums 2606A,2606B relative to the other. This permits use of the handles to applyforce at the fulcrums 2606A, 2606B on opposite sides of bending bridgeelement 216 to effective reshaping of the plate 200.

FIGS. 52 and 53 show a K-wire insertion tool 1700. FIG. 54 is across-sectional view of the distal portion of tool 1700 removablyattached to a preassembly 1722 that includes a bone plate 1720 and drillguide 1400 of FIG. 41. Bone plate 1720 is shown for discussion purposesand may be any one of the other bone plates described herein. Thesurgeon may use tool 1700 to hold and manipulate preassembly 1722 andalso to guide a conventional K-wire along the longitudinal axis of drillguide 1400 and into the bone.

Tool 1700 includes a distal end 1702, a proximal end 1704 and alongitudinal axis 1712 extending therebetween. Tool 1700 furtherincludes a cylindrical body 1714 with a bore 1710 aligned on axis 1712,extending between proximal end 1704 and distal end 1702 and sized toguide a conventional K-wire. Body 1714 includes a proximal grippingportion 1706 and a distal insertion portion 1708.

Gripping portion 1706 may have a cross-sectional diameter, for example,in the range of about 1 to 2 cm and may have a length, for example,about in the range of 3 to 10 cm. Gripping portion 1706 may also beprovided with a non-slip gripping surface 1705, which may be a knurledsurface or any one of a number of machined surfaces known in the art.

Distal insertion portion 1708 has a cross-sectional diameter that issized for slidable insertion into and removal from drill guide 1400, yethas sufficient frictional engagement in drill guide 1400 for the surgeonto use tool 1700 to hold and manipulate preassembly 1722. A similarK-wire insertion tool (but which does not extend all the way through thebore of the drill guide) is described in more detail in co-owned U.S.Pub. No. 20080015591A1, which is hereby incorporated by reference hereinin its entirety.

While particular embodiments have been described in detail, it isintended that the claimed invention be as broad in scope as the art willallow. Where the terms ‘approximate’, ‘approximately’ or ‘substantially’are used herein, such terms are to be defined as ±20 percent of a givennumber, amount, or relative position or location, as determined bycontext. Those skilled in the art will appreciate that one could makemodifications to the devices and methods described herein withoutdeviating from the spirit and scope of the claimed invention.

1. A bone plate for the internal fixation of a fractured proximal radiusbone, the proximal radius bone having a proximal articular surface witha surface axis extending through a center thereof, the bone plate, in anas machined configuration, consisting essentially of: a) a rigid bodywith proximal and distal ends defining a longitudinal axis, a medialedge and a lateral edge, an upper surface and a lower surface, the rigidbody including first and second body holes at least one of which isthreaded and defines a central axis; b) a first arm extending from themedial edge of the rigid body in a proximal-medial direction, the firstarm including a first ring element attached to the medial edge of thebody by a first bendable bridge element curved out-of-plane with therigid body portion, the first ring element including a threaded firstring hole defining a first thread axis angled relative to the centralaxis; c) a second arm extending from the lateral edge of the rigid bodyin a proximal-lateral direction, the second arm including a second ringelement attached to the lateral edge of the rigid body by a secondbendable bridge element curved out-of-plane with the rigid body portion,the second ring element defining a threaded second ring hole having asecond thread axis angled relative to the central axis; d) a third armextending proximally from the rigid body and including a third ringelement attached to the proximal end of the rigid body by a third bridgeelement, the third ring element including a threaded third ring holedefining a third thread axis; and e) a fourth arm extending distallyfrom the rigid body, the fourth arm including a fourth ring elementattached to the distal end of the rigid body, the fourth ring elementincluding a threaded fourth ring hole defining a fourth thread axis,wherein the first, second and third arms extend substantially parallelto form a trident, wherein the first, second and third arms have acombined stiffness that approximates within twenty percent the stiffnessof the rigid body, wherein each of the first and second body holes andfirst ring hole can receive a fastener for attaching the bone plate tothe bone, and wherein the first, second and third thread axes throughthe first, second and third ring holes converge towards the surface axisof the proximal articular surface of the radius bone when the plate ispositioned on the proximal radius so as to be substantially alignedthereon.
 2. A bone plate according to claim 1, wherein: the first,second and third arms have a combined stiffness that approximates withinten percent the stiffness of the rigid body.
 3. A bone plate accordingto claim 1, wherein: proximal portion of the lower surface along thelongitudinal axis is convexly curved, and the first and second arms arecurved such that portions of the first and second rings extend below thelower surface of the rigid body.
 4. A bone plate according to claim 1,further consisting essentially of: a first, a second, a third and acentral drill guide preassembled into the first ring hole, second ringhole, third ring hole and first body hole, respectively.
 5. A bone plateaccording to claim 4, wherein: each of the first curved, second curvedand third bendable bridge elements is less stiff than the rigid body,and wherein each of the first, second and third drill guides is adaptedfor application of a bending tool, such that a user may use a pair ofbending tools to apply a leveraging force to reconfigure any one of thefirst, second and third arms.
 6. A bone plate according to claim 5,further consisting essentially of: a fifth arm extending distally fromthe fourth ring element, the fifth arm including a fifth ring elementattached to the distal end of the fourth ring element by a fifthbendable bridge element, the fifth ring element including a fifth ringhole having a thread, the fourth ring hole including a fourth drillguide preassembled into the fourth ring hole, and the fifth ring holefor receiving a fastener and including a fifth drill guide preassembledinto the fifth ring hole.
 7. The bone plate according to claim 6,wherein: each of the fourth and fifth bendable bridge elements is lessstiff than the rigid body, and wherein each of the fourth and fifthdrill guides is adapted for application of a bending tool, such that auser may use a pair of bending tools to apply a leveraging force toreconfigure either of the fourth and fifth arms.
 8. The bone plateaccording to claim 7, wherein: each of the fourth and fifth bendablebridge elements is fragmentable, such that a user may use the pair ofbending tools to apply a leveraging force to fatigue fracture the fourthbendable bridge element in order to remove the fourth and fifth arms,and to apply a leveraging force to fatigue fracture the fifth bendablebridge in order to remove the fifth arm.
 9. A bone plate for theinternal fixation of a fractured proximal radius bone, the proximalradius bone having an articular surface, the bone plate for the proximalradius comprising: a) a rigid body with proximal and distal endsdefining a longitudinal axis, a medial edge and a lateral edge, an uppersurface and a lower surface, the rigid body including first and secondbody holes each of which can receive a fastener for attaching the boneplate to the bone; b) a first arm extending proximal-medially from therigid body, the first arm including a first ring element attached to thebody by a first curved bendable bridge element, the first ring elementincluding a first ring hole having a thread that defines a first threadaxis, said first ring hole able to receive a fastener for attaching thefirst ring element to the bone; c) a second arm extendingproximal-laterally from the rigid body and including a second ringelement attached to the lateral edge of the rigid body by a secondcurved bendable bridge element, the second ring element including asecond ring hole having a thread that defines a second thread axis, saidsecond ring hole able to receive a fastener for attaching the secondring element to the bone; and d) a third arm extending proximally fromthe rigid body and including a third ring element attached to theproximal end of the rigid body by a third bridge element, the third ringelement including a third threaded hole defining a third thread axis,said third ring hole able to receive a fastener for attaching the thirdring element to the bone, wherein the first, second and third arms havea combined stiffness that approximates within twenty percent thestiffness of the rigid body.
 10. A bone plate according to claim 9,wherein: the first, second and third arms have a combined stiffness thatapproximates within ten percent the stiffness of the rigid body.
 11. Abone plate according to claim 9, wherein: the first, second and thirdring elements have respective bone contacting surfaces, the bonecontacting surfaces of the first, second and third ring elementsoriented to seat on a sphere of a predetermined diameter.
 12. A boneplate according to claim 1, wherein: the first, second and third ringelements have respective bone contacting surfaces, the bone contactingsurfaces of the first, second and third ring elements oriented to seaton a sphere of a predetermined diameter.
 13. A bone plate according toclaim 3, wherein: the third arm is curved upwards away from the lowersurface of the rigid body.